On my website sometime back, I added a page on the image fragment sent back by the Mars-3 Lander. I released serveral versions, including the best quality processing using othodox techniques I would use on other images plus colorization here:http://pages.preferred.com/%7Etedstryk/fragmentc.jpgHowever, I released another image, which I called a "What if" image. This image can be seen here http://pages.preferred.com/%7Etedstryk/m3s5b.jpg It was produced via extreme processing of the original data to make a Mars-like scene, but I made it clear on my website it was only a speculative image. I strongly doubt if the raw data even shows Mars at all - it could be all noise. But since this mode of processing looked strangely Viking-like, I figured I would put it on the web. I was warned by several, who said that while fun, some kooks might take it seriously. My response was that I really don't care what kooks think. Then I noticed this web page:http://en.wikipedia.org/wiki/Mars_2They used the overprocessed image. I feel like it is being presented as a true photograph. This is of concern.

Thanks. I will be updating the Phobos-2 section soon. I have some reprocessed Thermoscan stuff about ready to go up. As for the Wikipedia problem, I have been able to edit the caption one sees when one clicks on the image. However, it won't let me edit the caption under the image on the original page. But at least I did get a disclamer in. It is neat to speculate that this might be a glimpse of Mars, but it most likely is just noise. I don't want people to come to a different conclusion based on this image, which, as I said, is very much overprocessed. It is, as I said, an experiment in the area of "what if"

With regard to the Soviet Mars landers, I now think that they may have been "done-in" by the lowdensity Martian atmosphere. Perhaps, the three Soviet probes that did land on Mars came closer to success than may have been earlier believed. The recent realization that low density during the EDL of Spirit may have brought that mission to a sad end has caused me to reconsider other missions, such as Beagle 2, the MPL and the Soviet Mars 2, Mars 3 and Mars 6 landers.

It appears that the Mars 2 qnd 3 landers were notdesigned to communicate back to the Earth until after landing, much like the Mars Polar Lander. If this is true, then perhaps Mars 2 didn't simply "plow into" Mars as is popularly believed. Perhaps, its EDL sequence was executed, but low density Martian atmospheric conditions caused it to be damaged upon landing. The same may be true for Mars 3 and Mars 6.

In addition, it appears that the Soiets modified Mars 6 so that it did transmit during EDL as it radioed back data on Martian atmospheric composition (which threw a scare into the Viking mission sceince team).

I would be interested in the thoughts of others in the UMSF community and in any additional info that they may have on the Soviet missions.

The Soviets actually do firmly know why Mars 2 failed, as V.G. Perminov said in his interesting historical document "The Difficult Road to Mars". They didn't trust the accuracy of their radio tracking network, so they incorporated an optical guidance system into the Mars 2 and 3 orbiters to allow them to calculate the optimal course for their final pre-arrival midcourse correction. Unfortunately, the Soviets had slightly inaccurate data on Mars' ephermeris, and so -- while Mars 2's onboard system worked as planned -- it ended up putting its lander onto a course directed at too steep an entry angle, which would have led to the lander crashing in any case before its parachute could properly brake it.

The Bad Luck Fairy that has always haunted the Russian Mars program struck in a particularly brutal way that time. First, the next year the US (as part of a planetary science data exchange program) provided the Soviets with a corrected Martian ephemeris -- and, second, it turned out afterwards that if the onboard optical system HADN'T made that correction, Mars 2's preexisting approach trajectory would, by pure luck, have put the lander on a properly shallow entry!

The failures of the Mars 3 and 6 landers remain more mysterious. Perminov expresses his suspicion that Mars 3 might perhaps have been knocked out by an electrostatic discharge from the giant dust storm it landed in. As for Mars 6, it failed at about the time its final solid-fueled braking rocket was supposed to fire -- meaning that the rocket could have fired at an inappropriate time due to Martian conditions, failed to fire at all, or exploded.

As for Mars 6, it failed at about the time its final solid-fueled braking rocket was supposed to fire -- meaning that the rocket could have fired at an inappropriate time due to Martian conditions, failed to fire at all, or exploded.

It is thought that it probably fired too late...in other words, it was too close to the surface when it fired, so it was still going too fast when it hit. It is because the timing was a bit off. Still, the fact that the timing was as close as it was is remarkable, given that, due to computer problems, Mars-6 had been unable to receive ground commands for five or six months at this point! It was purely operating on pre-programed sequences. In fact, the Russians were expecting this, although they were hoping for a stroke of luck, because they realized, as it approached and the trajectory was refined, that this was a problem, but, since Mars-6 couldn't be commanded, they were helpless to do anything about it.

However, the failure of Mars 4/5/6/7 was really not bad luck. It was bad microchips (which is what made Mars 6 uncontrollable, Mars 7 miss the planet, Mars 5 depressurize, and Mars 4 unable to fire its breaking motors). The scientists and engineers knew it and wanted to delay the mission until the next window to replace them, but since there was a chance that, as Mars-6 came very close to doing, they still might last just long enough to arrive and touch down for a brief surface mission to get the "first," the political powers ordered them to proceed with launch. They were going to try again in 1975 with a similar lander with good microchips, which may well have suceeded, but since Viking was much more capable (although it would have had some experiments that Viking didn't), and the Soviets had already made it to Venus, once it was clear that Viking would launch in the 1975 window, they mission was cancelled. Had Viking been delayed, it would have launched.

Oh, yes, Perminov goes into great detail about the lousy microchips (due to a decision made by one lower-level manager to cut costs by manufacturing them using aluminum instead of gold). However, it's doubtful that a "timing error" was the problem, because the ignition moment for the braking rocket on the Soviet landers (as for our own three rough Mars landers) was supposed to be triggered by a radar altimeter -- one could hardly depend on a preset timer for it. Of course, the microchips could very easily have fouled that up. (Or, of course, given what we now know about the atmosphere-related dangers of Mars landings, it could have been a simple wind gust or lower-than-normal upper air density than ruined Mars 6.)

As for their instrumentation (on which Perminov also provides useful data), the only instruments they carried that were not on the Vikings were the penetrometer and gamma-ray densitometer on that tiny tethered matchbox-sized "rover" they carried. The other instruments were two facsimile cameras, weather sensors, an atmospheric mass spectrometer, and an X-ray spectrometer for soil analysis on a boom fastened to one petal tip. No life-related experiments at all, but of course the additional surface geological data they could have provided would have been useful.

The Soviets actually do firmly know why Mars 2 failed, as V.G. Perminov said in his interesting historical document "The Difficult Road to Mars". They didn't trust the accuracy of their radio tracking network, so they incorporated an optical guidance system into the Mars 2 and 3 orbiters to allow them to calculate the optimal course for their final pre-arrival midcourse correction. Unfortunately, the Soviets had slightly inaccurate data on Mars' ephermeris, and so -- while Mars 2's onboard system worked as planned -- it ended up putting its lander onto a course directed at too steep an entry angle, which would have led to the lander crashing in any case before its parachute could properly brake it.

The Bad Luck Fairy that has always haunted the Russian Mars program struck in a particularly brutal way that time. First, the next year the US (as part of a planetary science data exchange program) provided the Soviets with a corrected Martian ephemeris -- and, second, it turned out afterwards that if the onboard optical system HADN'T made that correction, Mars 2's preexisting approach trajectory would, by pure luck, have put the lander on a properly shallow entry!

The failures of the Mars 3 and 6 landers remain more mysterious. Perminov expresses his suspicion that Mars 3 might perhaps have been knocked out by an electrostatic discharge from the giant dust storm it landed in...

This is a discussion we should have been having two years ago, right after the MER's descended more rapidly than expected...and it would be helpful if complete engineering Doppler and accelerometer data would be made public so that we can work the problem. Sheeesh.

Perminov's speculation that Mars 3 suffered a static incident is just that: He pointed out probes entering the Venician atmosphere snap crackled and popped, but he has no data from Mars to support this guess. We have had two probes scurrying around Mars for two years now without a single mention of a static event, making Perminov’s theory even more suspect. (Spirit and Opportunity didn’t even experience plasma blackouts.)

Likewise, blaming the Mars 2 failure on both a bad ephemeris and a bad self-correction is a little like insisting the failures of both Beagle and the Polar Lander were absolutely caused by bad engineering, now that another likely suspect has emerged.

There have been a lot of hints something isn’t right in earlier missions: Both Viking craft experienced accelerations that indicate an ‘over performance’ of the parachutes, while the Pathfinder EDL indicated an ‘under performance’ of the same design. I think both characterizations are in error: The Pathfinder did not contain accelerometers, relying on Doppler, while Viking did not have Doppler, but did have accelerometers. If you run the numbers, it is easy to see how in both cases greater acceleration than expected would end up as puzzling drag coefficients. Too many degrees of freedom! More sensors needed!

It is no secret my own bias towards an exceptional solution skews my interpretations of these events, but until we have all the facts on the table, it is difficult to judge which of the many possible scenerios have led to so many failures. PhilHorzempa’s correct; a reevaluation is in order, and for heaven’s sake let’s figure out how to properly characterize the atmosphere!

and it would be helpful if complete engineering Doppler and accelerometer data would be made public so that we can work the problem. Sheeesh.

Have you actually looked at the data that have been released to assess their adequacy? The pre-entry state of the MERs, which is what people have complained about, are on the NAIF FTP site, I believe. All of the raw data appears to be out there to do whatever EDL reconstruction you want; I don't think that the MR doppler tracking is actually useful for the reconstruction, but I believe it was archived with the MOC PDS releases quite a while back.

--------------------

Disclaimer: This post is based on public information only. Any opinions are my own.

This discussion is very relevant to future Mars landers such as Phoenix and MSL. I have heard that significant funding ( about $20 million?) was added to the Phoenix project in response to results from the MERs' EDL. Other than that cryptic info, there has been silence about this from the Phoenix team. In fact, in an exchange of emails with one of the Phoenix team, I learned that they are convinced that the MPL was desroyed by the famous software bug that the Mishap Board uncovered.

The software reset error on the Polar Lander is a good suspect. However, I worry that, with a suspect in hand, the other risks are being ignored. To me, the biggest risks are this uncertainty in Martian atmospheric density and the unexplained oscillations experienced by the ME Rovers.

I agree with TheMessenger that we need to adequately instrument ALL future landing missions. Also, NASA should be more open about this issue and open to assistance from the UMSF community.

Does anyone have insight into what, if anything, the Phoenix and MSL teams are doing to deal with this landing risk?

Sorry I can't cite a reference for this, but it seemed I read somewhere the electrical effects noted during Venusian atmospheric descent were thought due to various compounds and elements in the atmosphere condensing onto the relatively colder external surfaces of all the Venus probes. Local precipitation if you will.

If this be the case, would there be a similar mechanism for Mars?

(other than aerostatic charging as a result of friction with the Martian air)

Have you actually looked at the data that have been released to assess their adequacy?

Yes and no. I have made inquires, and been told the engineering data is not going to be made publicly available.

QUOTE

The pre-entry state of the MERs, which is what people have complained about, are on the NAIF FTP site, I believe.

All of the raw data appears to be out there to do whatever EDL reconstruction you want; I don't think that the MR doppler tracking is actually useful for the reconstruction, but I believe it was archived with the MOC PDS releases quite a while back.

Paul Withers wrote in an MER EDL paper he has submitted to Icarus, that he had to make a lot of approximations concerning initial conditions - perhaps the needed information is available now at the NAIF FTP site...whatever and where ever that is. If it is where I have been looking before, there are a lot of 'expected' tables, but the "reconstructed" or actual descent data is just not there. Paul emailed to me that he thought some of the data is ITAR restricted, but I don't see why. He also said that a well-funded study of the MER EDLs - comparable to earlier missions, is not 'in the budget' - I assumed he meant NASA isn't really taking these things apart, but I have been wrong before.

I've been raising my hand and holler'n that I think I can see a stunning trend for a year-and-a-half now. It is hard to get attention when so few people seem to know that the MERs almost splatted - Pathfinder too. As far as I know this is the first really public admission the missions were in jeopardy:

"After having some business dealings with men, I am occasionally chagrined, and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

I realize it will be many years before the Mars 3 site is investigated first hand, but I do hope the team has your enhanced photo with them.

I realize you are qualified to judge the degree of image processing you administered to get the 'Viking' looking result, but, can any amount of processing put consistent shadows on the correct sides of all the boulders in your enhancement? Me thinks there is more than a slight chance you've come up with something significant.

Paul Withers wrote in an MER EDL paper he has submitted to Icarus, that he had to make a lot of approximations concerning initial conditions - perhaps the needed information is available now at the NAIF FTP site...whatever and where ever that is. If it is where I have been looking before, there are a lot of 'expected' tables, but the "reconstructed" or actual descent data is just not there.

If you're going to make sweeping assertions, it might help to exhibit more cognizance of the process involved. The NAIF FTP site (naif.jpl.nasa.gov) is the standard place where JPL trajectory information is released. The file /pub/naif/MER/kernels/spk/spk_a_c_030610-040104_recon.bsp on that site is, according to its label, "a reconstructed cruise trajectory for MER-A, beginning at TECO and ending at atmospheric entry." There is a similar file for MER-B. If Withers is unaware of those files, you might want to make him aware. If there's something inadequate about the information, I'd be curious as to what.

As previously noted, that state information and the EDL engineering telemetry archive, which has been released and is available on the PDS atmospheric node, are all the information I can think of that would be useful for reconstructing the entries of the MERs.

I'm no apologist for JPL, but carping on this topic would appear to be unjustified.

Now, it may be that what Withers is lacking is a detailed description of the MER aeroshell composition, shape, etc. The design details of reentry vehicles are covered under ITAR for what would seem to be legitimate reasons. I haven't tried to find those details, nor do I know what data precision might be required. There's a fair bit of info in http://library-dspace.larc.nasa.gov/dspace...ndle/2002/11213

--------------------

Disclaimer: This post is based on public information only. Any opinions are my own.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted.
Do not reproduce without permission. Read
here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the
individual posters and do not necessarily reflect the opinions
of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer
UnmannedSpaceflight.com moderation team is wholly independent
of The Planetary Society. The Planetary Society has no influence
over decisions made by the UnmannedSpaceflight.com moderators.

SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society
and is funded by donations from visitors and members. Help keep
this forum up and running by contributing
here.